Dry areas appearing when using GC50

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Dry areas appearing when using GC50

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MarkMK	MarkMK posted 10 Years Ago HOT Topic Details
Group: Forum Members Posts: 338, Visits: 2K	Hi all A couple of recently infused parts have demoulded with small dry areas of crazing on the part surface. I'd sprayed GC50 into the mould first, left overnight and infused the next morning.In both cases full vac was achieved and drop-tested for 30 mins before infusion All other aspects of the process were adhered to carefully. If there was anything amiss I'd have expected to see any blemishes to appear below the outer gelcoat surface so was puzzled by the surface imperfections Could it perhaps mean that I need to apply the gelcoat a little more thickly, as I'm usually concious of not spraying too much and creating sags or uneveness that might affect the appearance of the cured fabric. Thanks Mark
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Warren (Staff)	Warren (Staff) posted 10 Years Ago HOT Post Details
Group: Administrators Posts: 2.5K, Visits: 8.5K	The picture looks like there are actual voids there not alligatoring. The voids are right through the gelcoat. We dont recommend spraying acetone onto the gc50 so its possible that eat through the gel leaving voids to trap air. Warren Penalver Easy Composites / Carbon Mods - Technical Support Assistant
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ChrisR	ChrisR posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 363, Visits: 3K	A bit more info may be required: What's the stack sequence? How long did you pull the vac before sealing for the drop test? How fast was the infusion mesh? Have you any pictures of the thing bagged up and ready to infuse?
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MarkMK	MarkMK posted 10 Years Ago HOT Post Details
Group: Forum Members Posts: 338, Visits: 2K	Sorry, no pics of set-up Chris, but will likely run another part this week. Stack was two plys of 200g twill backed with one of 450g. This was topped with peel-ply and EC mesh which, I believe, is medium flow. Everything was sealed quite soon after full vacuum was read on the guage and tone of the pump indicated no more air was being drawn. Warren - An interesting point regarding the acetone as I'm sure that one of Matt's tutorial videos shows him using it on the Fiat bonnet infusion. It does feel kind of logical, though, that this might have had a part to play in weaking the gelcoat surface, so I'll likely avoid it now.
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Dry areas appearing when using GC50

MarkMK - 10 Years Ago

Are the parts de moulding easily? Is the crazing happening during removal? Alternatively, is it...

ajb100 - 10 Years Ago

Could you quickly just clarify what you mean by crazing? I have heard people use crazing and...

Hanaldo - 10 Years Ago

If you can take a photo we shall try and work out what is going on. Actual cracking would tend to...

Warren (Staff) - 10 Years Ago

Hopefully the attached pic will provide a bit more insight. I'm guessing it's what's commonly...

MarkMK - 10 Years Ago

It looks like dry spots from the infusion rather than a surface problem

ChrisR - 10 Years Ago

I agree, it does, but the imperfections have also broken the outer gelcoat when previously I'd only...

MarkMK - 10 Years Ago

This also happened to me when I closed the entrance of the resin and after too much time the vacuum...

Jacopo Carbonio - 10 Years Ago

I can understand it had I been shutting off the resin feed prior to the vacuum line, as you...

MarkMK - 10 Years Ago

The picture looks like there are actual voids there not alligatoring. The voids are right through...

Warren (Staff) - 10 Years Ago

A bit more info may be required: What's the stack sequence? How long did you pull the vac before...

ChrisR - 10 Years Ago

Sorry, no pics of set-up Chris, but will likely run another part this week. Stack was two plys of...

MarkMK - 10 Years Ago

There is a note in that video that the formula for GC50 has been changed and acetone no longer works...

Brian_s - 10 Years Ago

Yes the formulation changed meaning acetone does not activate it in the same way as before. Acetone...

Warren (Staff) - 10 Years Ago

Doh! That'll teach me to pay closer attention. Thanks gents, glad I raised it now rather than just...

MarkMK - 10 Years Ago

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